A Russian cosmonaut and U.S. astronaut took a walk in space Thursday to perform maintenance on the international space station. They took measures to deflect harmful rocket exhaust away from future spacewalkers.

Cosmonaut Yuri Onufrienko and astronaut Dan Bursch spent six hours outside the station to mount shields over six rocket thrusters on the rear of the outpost's crew quarters.

The thrusters maintain the station's orientation in orbit, but they emit dirty fumes that could stick to a crewmember's spacesuit and contaminate the station's interior if brought inside.

The metal shields the two spacewalkers installed will either contain the residue or deflect it into space.

Before they re-entered the outpost, they wiped off their suits to remove any residue that may have collected.

Another task they performed on the outing was mounting three antennas for future amateur radio operations. The first antenna was installed on a spacewalk earlier this month.

This was the second of three spacewalks for the current station crew, which arrived for a five-month stay at the complex in early December. The third is scheduled for late next month when Dan Bursch and fellow astronaut Carl Walz preposition equipment that will be used in April by a visiting space shuttle team during installation of a truss.

The truss will be a platform on which U.S. electrical power hardware will be mounted. It will also become the attachment point for future European and Japanese research laboratories.